“Our first shipment of 500 bottles of fresh air were sold in four days,” co-founder Moses Lam says in a telephone interview with the Telegraph.

A crate containing 4,000 more bottles is making its way to China, but he says most of that shipment has been bought.

Banff National Park in Alberta, Canada (Photo: Alamy)

A 7.7 Litre can of crisp air taken from Banff National Park in the majestic Rocky Mountains range sells for roughly 100 yuan (£10), which is 50 times more expensive than a bottle of mineral water in China.

The levels of pollution are so high it makes selling bottled air to China a viable business.

Most of their customers live in big cities in the northeastern and southern parts of China where severe pollution warnings have become a common occurence.

State news agency Xinhua has posted a picture online of the city centre barely visible under a thick soup of smog on Tuesday and reflects local frustrations with the caption: “Heavy smog hit China, again!”

Vitality Air’s Mr Lam admits that he started out the company as a joke as well when he and co-founder Troy Paquette filled a plastic bag of air and sold it for less than 50 pence on the auction site Ebay.

A second bag sold for $160 (£105).

“That’s when we realised there is a market for this,” says Mr Lam.

Vitality Air sells bottled fresh air and oxygen across North America, to India and the Middle East. But China remains its biggest overseas market.

The company’s China representative, Harrison Wang, says their customers are mainly affluent Chinese women who buy for their families or give away as gifts. But he says senior homes and even high end night clubs have also stocked up on their product.

“In China fresh air is a luxury, something so precious,” says Mr Wang.

He says a number of distributors have contacted them to sell their products.

The smog in China is so bad that people are actually buying bottled air from Canada

While pollution levels are reaching record highs in China, a Canadian start-up is finding a way to make a profit. Vitality Air, a company that sells canned air and oxygen, is seeing a huge demand from users in China.